1. Field of Technology
The describe technology relates to a developer collecting device and an image forming apparatus having the developer collecting device.
2. Description of the Related Art
In recent years, it has been gradually more common in an image forming apparatus to shift printing in black and white to printing in full color. Moreover, along with development of the image forming apparatus, a color image forming apparatus has been utilized for general purposes. Among the color image forming apparatuses, especially for an image forming apparatus which employs an electrophotographic system, anindirect transfer system has been often proposed in an attempt to meet miniaturization of the apparatus and speeding up of color image formation. The indirect transfer system is characterized by the following processes in formation of a color image onto recording paper Firstly, a developer image is formed (first transfer) by stacking image information separated in color for each color component from an electrostatic latent image bearing member (hereinafter may be referred to as a photoreceptor) respectively provided on a plurality of image forming units (also referred to as a process printing unit) onto an intermediate transfer body. And then, the developer image processed by the first transfer is totally transferred (second transfer) onto the recording paper serving as a transfer-subjected medium.
In general, it is well known that, when the first transfer is carried out from a photoreceptor to an intermediate transfer body at a transfer step in the image formation, not all the developer which forms a developer image on the photoreceptor is transferred onto the intermediate transfer body, but a little developer remains on the photoreceptor. it is known that a transfer efficiency of the first transfer is approximately 90%. Also at a second transfer step for transferring the developer image on the intermediate transfer body onto the recording paper, residual developer is generated as in the above case.
Consequently, the image forming apparatus is usually provided with a cleaning device for collecting the residual developer remaining on the photoreceptor and the intermediate transfer body at the first and second transfer steps and in addition, a developer collecting device for collecting as waste developer the residual developer which has been cleaned by the cleaning device. However, in order to provide a plurality of the developer collecting devicees for a plurality of the image forming units and the intermediate transfer body, a larger space in the apparatus will be necessary therefor, which is not favorable in terms of compact design, decrease of user's operability, and pollution inside the apparatus due to the waste developer.
In consideration of the above points, the applicant has proposed an integrally-formed developer recovery container for accommodating waste developer generated from a plurality of residual developer sources in Japanese Patent Application No. 2004-335499 so as to solve the above problems. In the above proposal, integration of the container is realized, and problems about compact design or the like can be solved. However, a plurality of detecting sensors are used for determining whether or not the waste developer container is mounted on the apparatus and whether or not the waste developer container is filled up with the waste developer, so that the above proposal includes a problem of spaces necessary for mounting a plurality of detecting sensors and a problem that determination operation becomes complicated.
In a related art, a photosensor is utilized for determining whether or not a waste developer container for accommodating waste developer is present, and determining a state of the waste developer accumulated inside the waste developer container (for instance, referred to Japanese Unexamined Patent Publication JP-A 2003-345203)
In the art disclosed in JP-A 2003-345203 is provided a detecting switch which detects whether or not a waste toner box is mounted on an apparatus main body, and a photosensor which operates either in a translucent state or in a light shielding state when the detecting switch is turned on while the photosensor is brought to the same state as the translucent state when the detecting switch is turned off. When the detecting switch is turned on and the photosensor is in the light shielding state, it is determined that the waste toner box is filled up with the waste developer.
However, the art of JP-A 2003-345203 includes a problem that significantly careful check is required for the switches or the like, in order to determine whether the waste toner box is mounted and full with waste developer or the waste toner box is not mounted but a signal indicating a full state is outputted, because the photosensor is brought to the same state as the translucent state even when the detecting switch is turned off, specifically when the waste toner box is not mounted on the apparatus main body.
Further, in a method of detecting an accommodation capacity of the waste toner in the waste toner box by the photosensor, false detection may be caused since the waste toner accumulated in the container is excellent in fluidity, with the result that the waste toner contaminates an inner wall portion of the container by flowing of the waste toner inside the container, which leads decrease of detecting accuracy of the photosensor.